基于软硬件协同设计的解释器指令分派方法

为了降低指令分派造成的运行开销以提高解释器的性能,提出了一种采用软硬件协同设计的解释器指令分派方法。其核心思想是在软件层面通过对指令分派表进行优化以消除了代价较高的地址常量加载操作,在硬件层面通过扩展处理器的访存指令进一步实现基于硬件支持的访存加速。软硬件协同设计可以最大限度地降低由指令分派引入的运行时开销,从而提升解释执行的效率。试验结果表明,该方法能够显著提升解释器的性能。对于SPECjvm98和Da Capo测试集,解释器总体性能提升了11.5%,且单项性能的最大提升幅度高达15.4%。该方法通用性强,实现代价低,适用于现代主流处理器平台上高性能解释器的设计和优化。     

软硬件协同设计和系统级仿真探索

简要介绍了系统级芯片设计的软硬件协同设计、协同仿真技术和SoC开发中系统级协同仿真的工具,并给出了一个在CCSS (CoCentric system studio)环境下完成软硬件协同仿真的实例。     

面向多处理器SoC设计的低功耗软硬件划分

提出了解决多处理器SoC的低功耗软硬件划分问题的方法--基于神经网络的禁忌搜索算法.其基本思想是:真实的生物神经元具有抑制重复激活的阻尼特性,这与禁忌搜索对重复搜索加以限制相类似,因此设计具有阻尼特性的神经网络实现禁忌搜索算法,受阻尼特性抑制的神经元对应禁忌活动.由于神经网络复杂的动态特性和禁忌搜索优秀的全局搜索能力,该算法能够有效地跳出局部最优解.对真实任务图的实验表明,与遗传算法相比,该算法不但具有搜索速度上的优势,而且所得到的绝大部分软硬件划分方案有更低的系统功耗.     

结构减振设计的协同优化分析

建立一种适用于工程结构减振设计的协同优化模型。在学科级优化子模型中,分别使用了不同的目标函数;在系统级优化子模型中,以如何获得尽可能接近于子学科独立优化的最优解为目标函数。系统级目标函数消除了量纲和数量级的影响。该模型采用分布协同的双层结构,允许在每一级优化中使用不同的优化策略。以减速器和板梁柱混合结构为例,对其进行了单学科和多学科优化分析。实例结果表明,在结构减振设计时,采用协同优化模型进行优化设计,不仅可以有效的降低结构动力特性参数,而且优化后结构的综合性能更佳,说明该模型能应用于实际工程结构的减振设计。     

通用电机产品族协同设计的模糊优化

产品族设计是大规模定制中的核心内容,许多文献在假定产品特征确定情况下,采用平台参数和非平台参数,提出了大规模定制下的产品族设计优化方法。基于产品族设计理念,针对含有不确定特征的产品族设计中的一种基本类型——产品参数与产品功能之间的映射含有模糊系数的情形,建立一种对平台参数和非平台参数进行协同优化的模糊双层线性规划模型,利用有关模糊算法对模糊条件下的通用电机产品族协同设计进行优化。     

复杂产品的多学科鲁棒协同设计优化方法研究

为了处理好复杂产品各子系统之间的耦合关系以及各子系统的异构性问题,以协同优化(CO)算法为基础,结合系统不确定分析(SUA)方法和近似不确定传播(IUP)方法,构建了多学科鲁棒协同设计优化算法框架.在设计变量的不确定性能够被概率分布函数描述的情况下,此算法框架能够解决复杂产品的设计优化问题.通过对梳齿式微加速度计的多学科鲁棒协同优化设计算例的计算,验证了此算法在输入参数存在微小扰动的情况下能够有效提高设计解的鲁棒性.     

公路设计与仿真协同框架

现在随着人民群众的生活水平的上升,人们越来越重视公路设计与仿真协同框架的建构,公路设计是采用某种适合的方式方法合理地设计公路,而仿真协同框架的建构,就需要我们重视两个方面,即仿真和协同,仿真,也就是模拟真实,采用某种不常用手段来达到符合实际使用标准的目的,而协同,就是要在公路设计中,各个技术协同配合,共同建构一个合理的设计框架,这更需要我们认真仔细地去思考和讨论。     

嵌入式设备电源控制系统的CAN通信软硬件设计

为解决电源监控系统中存在的数字化程度低、实时性差、准确度和可靠性低等问题,在研究CAN协议的原理及应用技术的基础上,采用外挂Microchip MCP2515 CAN控制器的设计思想,完成基于AVR单片机的CAN通信软硬件设计,满足电源控制系统策略的需要。该文给出CAN总线的整体结构及控制器、收发器等组成部分硬件及软件的设计与实现,并对系统进行网络负载分析及实时性分析。实际运行表明:该系统可实现报文的发送、接收等功能,可靠性强、通信实时性好。另外,电气隔离电路的设计,进一步提高系统的抗干扰能力;同时,软件设计部分采用自顶向下的模块化设计方法,增强系统的可移植性。     

基于FPGA的软硬件协同的多表哈希连接加速器

多表连接操作难以实现硬件加速.一方面,多表连接请求中表的数目不确定且连接方式多变,这种灵活的计算请求与固定的硬件行为之间存在矛盾;另一方面,多表连接的中间结果随表的增加而扩充,数据结构的管理和维护也要求更高的硬件开销.为支持灵活高效的多表连接计算,本文提出一种软硬件协同的优化方法.软件部分,将多表连接抽象为正向和反向2 种计算模式并支持不同方式的多表连接.硬件设计采用访存和计算协同优化的方法:设计一种规则的硬件哈希表结构以提高内存访存带宽;设计支持正反向计算的同构专用计算引擎,配置多数据通道和指令控制系统实现高效的并行运算,提升多表哈希连接的计算效率.实验结果表明,相比中央处理器(CPU)执行表连接操作,单计算引擎能够提升性能9.2～11.0 倍.通过多路并行的技术,实现 8 路并行的多表哈希引擎,能够充分利用板卡片外(DDR)内存带宽,实现相比CPU超过71.1 倍的性能提升.     

Novel collaborative optimization framework with a negotiation model for satellite system design

This article proposes a novel collaborative optimization (NCO) framework that uses a persuasive multi-agent negotiation method for satellite system design. Satellite system design is a typical multi-disciplinary design optimization problem. The traditional collaborative optimization (CO) is a competitive method but has the disadvantage of inefficient convergence caused by the interdisciplinary compatibility constraints in system-level optimization. By introducing the multi-agent negotiation method, an NCO framework is proposed, in which the system-level and subsystem-level variable negotiations replace the system-level compatibility constraints in traditional CO. The negotiation introduces a modification for candidate values that do not satisfy the compatibility constraints, ensures that an alternative compatible candidate will be obtained and has high convergence efficiency. Two numerical benchmark functions and a multi-disciplinary satellite system design are used to analyse the performance of the proposed NCO. The simulation results show that NCO can efficiently ensure parameter interdisciplinary matching and advanced convergence performance.     

A unified parametric design approach to structural shape optimization

This paper presents a general parametric design approach for 2-D shape optimization problems. This approach has been achieved by integrating practical design methodologies into numerical procedures. It is characterized by three features: (i) automatic selection of a minimum number of shape design variables based on the CAD geometric model; (ii) integration of sequential convex programming algorithms to solve equality constrained optimization problems; (iii) efficient sensitivity analysis by means of the improved semi-analytical method. It is shown that shape design variables can be either manually or systematically identified with the help of equality constraints describing the relationship between geometric entities. Numerical solutions are performed to demonstrate the applicability of the proposed approach. A discussion of the results is also given:     

A versatile software tool for microwave planar radar absorbing materials design using global optimization algorithms

A computer-aided design (CAD) tool for the design of planar multi-layer coatings with high absorption for a desired frequency and angle range is presented. The tool uses deterministic and evolutionary optimization design methods. Both single and multi-objective design algorithms can be used and a single absorber design or the Pareto front can be found accordingly. A novel design technique utilizing PSO is also presented. A user-defined or a pre-defined design case can be selected interchangeably. The choice of selecting materials from pre-defined database is also available. The tool can be useful for both educational and research purposes. The efficiency of the tool is demonstrated through several design cases that are in agreement with existing literature data.     

A new optimization algorithm for solving complex constrained design optimization problems

This article presents the performance of a very recently proposed Jaya algorithm on a class of constrained design optimization problems. The distinct feature of this algorithm is that it does not have any algorithm-specific control parameters and hence the burden of tuning the control parameters is minimized. The performance of the proposed Jaya algorithm is tested on 21 benchmark problems related to constrained design optimization. In addition to the 21 benchmark problems, the performance of the algorithm is investigated on four constrained mechanical design problems, i.e. robot gripper, multiple disc clutch brake, hydrostatic thrust bearing and rolling element bearing. The computational results reveal that the Jaya algorithm is superior to or competitive with other optimization algorithms for the problems considered.     

扭矩扳手检定装置受力杆结构优化分析

利用ANSYS Workbench对扭矩扳手检定装置受力杆进行静力学分析,模拟其对扭矩扳手进行扭矩值检定时受到应力、应变及变形的情况,根据得到的数据对其进行结构优化设计、轻量化设计。     

Two-level parallelization for finite-element based design optimization via case studies

Computing clusters created with commodity chips are gaining popularity owing to relative ease of assembly and maintenance compared to a supercomputer. Such clusters are able to solve much larger problems owing to increased memory and reduced compute time. The challenge, however, is to develop new algorithms and software that can exploit multiple processors. In this paper we discuss the parallel processing options and their implementations in a gradient-based design optimization software system. The main objectives are as follows—(a) implement a design optimization methodology for sizing, shape and topology optimization using two-level parallelism and (b) provide a benchmark in the area of FEA-based design optimization for studying speedups with increasing number of processors to speed development of effective parallel algorithms. The two-level parallelism is implemented using nested parallel gradient calculations in conjunction with parallel FEA, and parallel line search with parallel FEA. Two case studies involving topology and shape optimization are studied in detail and they include three-dimensional finite element meshes with about 160 000 hexahedral elements and about 175 000 nodes. Furthermore, the case studies have been implemented using a workbench where the topology and shape optimization have an interface with a commercial CAD package, permitting a solid model representation of both the initial and the final optimized part.     

Adaptive improved response surface method for reliability-based design optimization

Reliability-based design optimization (RBDO) requires the evaluation of probabilistic constraints (or reliability), which can be very time consuming. Therefore, a practical solution for efficient reliability analysis is needed. The response surface method (RSM) and dimension reduction (DR) are two well-known approximation methods that construct the probabilistic limit state functions for reliability analysis. This article proposes a new RSM-based approximation approach, named the adaptive improved response surface method (AIRSM), which uses the moving least-squares method in conjunction with a new weight function. AIRSM is tested with two simplified designs of experiments: saturated design and central composite design. Its performance on reliability analysis is compared with DR in terms of efficiency and accuracy in multiple RBDO test problems.     

A framework for affective customer needs in product design

A systematic framework is proposed to conceptualize customer needs in product design. Customer needs were derived for current and future electronic devices in automobiles. Subjects rated their preferences for 15 product attributes on 10-point semantic differential scales. Using factor analysis, three generic factors were extracted, namely holistic attributes, styling and functional design. Depending upon the familiarity of the device, there were clear differences among potential customers. Unknown devices such as a navigation map were assessed first hand by using holistic attributes. Familiar designs such as car radio and cell phone were assessed using styling and functionality attributes. Customer reactions and preferences may be caused by product design parameters that operate either through their perceptual attributes or from the experience they acquire in using the artifacts or interfaces. There are both functional and affective needs. Functional (or cognitive) customer needs can be derived top-down, using product design features. Affective customer needs are difficult to derive top-down—typically they are evaluated by looking at several design propositions.     

Conceptual design and performance analysis of absorption heat pumps for waste heat utilization

The potential of the absorption cycle for recovering low temperature waste heat (60°C) as a first step towards the construction of a working system to provide process heat is assessed. The system is considered with lithium chloride-, lithium bromide-water solutions as working fluids.